Impact of Angiotensin Blockade on Development of Chronic Lung Allograft Dysfunction

Background: The renin-angiotensin-aldosterone system (RAAS) is responsible for a multitude of physiological functions, including immunological effects such as promotion of TGF-β and upregulation of IL-6 and IL-8 which are also implicated in the development of chronic lung allograft dysfunction (CLAD). Blockade of the RAAS pathway in pre-clinical models has demonstrated a decrease in these cytokines and pulmonary neutrophil recruitment. Objective: This study sought to evaluate whether use of RAAS inhibitor (RAASi) in lung transplant recipients impacted CLAD-free survival. Methods: In this retrospective, single-center study, 35 lung transplant recipients who received a RAASi post-transplant were compared to 70 lung transplant recipients not exposed to a RAASi and were followed for up to 5 years post-transplant. Results: The incidence of CLAD did not differ based on RAASi treatment (34.3% in RAASi vs 38.6%, P-value .668). This was confirmed with a multivariable Cox proportional hazards model with RAASi initiation as a time-varying covariate (RAASi hazard ratio of 1.01, P-value .986). Incidence of hyperkalemia and acute kidney injury were low in the RAASi group. Conclusions: This study demonstrated no association between post-transplant RAASi use and decreased risk of CLAD development. RAASi were also well tolerated in this patient population.

Impact of antimetabolite discontinuation following cytomegalovirus or BK polyoma virus infection in kidney transplant recipients

BACKGROUND

Cytomegalovirus (CMV) and BK polyoma virus (BKV) infection following kidney transplantation have been associated with allograft dysfunction and allograft loss. Reduction in immunosuppression is a mainstay of management yet has been associated with increased risk of rejection. According to international consensus guidelines, one approach to management of these viral infections is to discontinue the antimetabolite. Little is known surrounding long-term outcomes in these patients, and it remains unclear if consideration should be given to resuming the antimetabolite as variable re-escalation strategies have been reported. The objective was to describe episodes of rejection and identify risk factors for rejection following antimetabolite withdrawal after CMV or BKV DNAemia in kidney transplant recipients.

METHODS

This single-center, retrospective review evaluated adult kidney transplant recipients with a serum CMV or BKV DNA PCR ≥500 copies/ml who underwent antimetabolite discontinuation. The primary outcome assessed was the incidence of biopsy-proven acute rejection (BPAR).

RESULTS

One hundred fifty-nine patients were included. Overall, 14 patients (8.8%) experienced BPAR at a median of 1.6 years after antimetabolite discontinuation. Compared to CMV, discontinuation after BKV DNAemia was associated with a higher incidence of BPAR. Characteristics observed more frequently in patients with BPAR included younger age, female sex, higher initial viral load, and development of de novo donor-specific antibody (DSA).

CONCLUSION

These findings suggest that antimetabolite discontinuation after CMV or BKV DNAemia in kidney transplant recipients is a reasonable and safe approach. Further prospective studies investigating optimal immunosuppression management following CMV or BKV DNAemia in kidney transplant recipients are warranted.

Effect of Vasopressin Dose on Hemodynamic Response in Obese Patients With Septic Shock: A Retrospective Observational Study

BACKGROUND

No clear association between standard vasopressin doses and body mass index exists, despite potential pharmacokinetic and pharmacodynamic variability among patients with septic shock. It is unknown if higher doses may alter hemodynamic response.

OBJECTIVE

The purpose of this study was to evaluate the effect of vasopressin dose on hemodynamic response in obese patients with septic shock.

METHODS

A single-center, retrospective cohort study was conducted in adult, obese patients with septic shock receiving catecholamine vasopressors and vasopressin. Patients were analyzed according to vasopressin dose received: standard dose (≤0.04 U/min) and high dose (>0.04 U/min). The primary outcome was percentage change in norepinephrine equivalent (NEQ) dose.

RESULTS

A total of 182 patients were included in the analysis, with 136 in the standard-dose vasopressin group and 46 in the high-dose vasopressin group. There was no difference in percentage change in NEQ dose at 6 hours after standard- or high-dose vasopressin attainment (-28.6% vs -19.1%; P = 0.166). A greater increase in mean arterial pressure (MAP) at 6 hours was observed with receipt of high-dose vasopressin (23.3% vs 15.3%; P = 0.023). Duration of shock and length of stay were significantly longer in patients who received high-dose vasopressin, with no difference in in-hospital mortality.

CONCLUSION AND RELEVANCE

This represents the first analysis comparing standard and higher doses of vasopressin in obese patients with septic shock. Receipt of high-dose vasopressin was not associated with a difference in catecholamine requirement or improved outcomes. Further studies are warranted to provide guidance on the use of high-dose vasopressin in septic shock.